Conserving Seasonal Pans

Seasonal pans are shallow natural depressions that fill with rainwater during the wet season and gradually dry out during the dry months. Although they may hold water for only a few weeks or months each year, these temporary wetlands are important biodiversity hotspots, providing habitat for a wide range of specialised plants, invertebrates, amphibians and birds. More than 300 seasonal pans occur across Malilangwe, forming a diverse network of temporary wetlands that support a remarkable variety of aquatic life.

Our Seasonal Pan Research

One example of the biodiversity supported by Malilangwe’s seasonal pans is the fairy shrimp, a large branchiopod crustacean specially adapted to life in temporary wetlands. A 2015 study by Karen Tutyens recorded seven fairy shrimp species and one tadpole shrimp across 160 pans on the property. While species diversity varied among the reserve’s geological regions, it showed little relationship to pan size, depth, or even how long a pan held water. These findings suggest that biodiversity in Malilangwe’s seasonal wetlands is shaped by broader ecological processes operating across the landscape rather than by the characteristics of individual pans.

The study also revealed that the pans function as a connected network rather than isolated habitats. Many species occur across multiple geological regions, and subsequent research demonstrated that dormant shrimp eggs can be transported between pans by mud-wallowing animals such as elephants, buffalo and rhino. In this way, the movements of large mammals help shape the distribution of tiny aquatic organisms, highlighting the remarkable interconnectedness of Malilangwe’s ecosystems.

These temporary wetlands are also highly resilient. Many aquatic species survive the dry season as dormant eggs buried in the sediment, forming hidden “egg banks” that can persist through droughts and hatch when favourable conditions return. Together, these findings underscore the importance of conserving not just individual pans, but the entire network of seasonal wetlands that contributes to Malilangwe’s exceptional biodiversity.